Mr. Zhao called to ask: Recently, I have been feeling pain and discomfort in my right hip and crotch, especially when I walk. A friend said that this is a symptom of osteonecrosis of the femoral head. I am very worried. How can I diagnose and prevent osteonecrosis in its early stages? Doctor’s answer: It is not scientific to determine whether you have osteonecrosis of the femoral head just by the pain in your hips and buttocks. Femoral head necrosis is a disease in which the blood supply to the femoral head is interrupted or damaged, causing the death of bone cells and bone marrow components and subsequent repair, which then leads to structural changes in the femoral head, femoral head collapse and joint dysfunction. The age of onset of femoral head necrosis is mostly between 20 and 50 years old. Therefore, femoral head necrosis should be diagnosed and prevented early. The most common clinical symptom of femoral head necrosis diagnosis is deep pain in the groin, which is relieved after rest. As the disease progresses, intermittent pain gradually develops into persistent pain, triggering muscle spasm, joint movement restriction, and finally causing severe disability and claudication. In the early stage, patients may experience pain that is unnoticeable or only occurs when the hip joint is internally rotated, with a characteristic pain-resistant gait; when the femoral head has collapsed and there are necrotic fragments, there may be intra-articular popping (cracking sound), and the pain is aggravated and activity is limited when the hip joint is internally rotated. MRI is the best method to diagnose and early detect femoral head necrosis, while plain X-ray and CT can be used to understand the progress of femoral head necrosis. There are many causes of osteonecrosis, such as alcoholism, gout, renal bone atrophy, sickle cell anemia, systemic use of adrenocorticotropic hormones, and trauma. For the prevention of femoral head necrosis, first of all, we should pay attention to the protection of the hip joint, control weight, and avoid excessive weight bearing and accidental injury to the joint. Secondly, we should quit smoking, excessive alcohol consumption and other bad habits, as well as try to avoid the use of hormonal drugs.